The people who think coloured pencils are a "childish" medium have obviously never been in an art shop and ogled at the awesome quality insanely expensive coloured pencils or used them. I remember borrowing my cousin's Derwents to shade a technical drawing (he did architecture), could never look at normal "school" pencils the same way again so back when I still did traditional i started getting some mid range ones that I wouldn't feel guilty about using over A4 or larger works and felt nicer.

Watercolour does seem rather hard to master but you've managed it really well :)